I'm pretty much with you that the MCU and TASM can co-mingle, but you are way off here. Ant-Man is most certainly an Avenger, in fact he is more of an Avenger than a solo hero. I'd venture to say that we only get one Ant-Man film and then the rest of his appearance will be in Avenger movies.

There are other characters I want to see in the Avengers more than Hank. I don't dislike him in any way, but I don't find his character interesting either.